/**
 * Pre-step injections of the DSH harness.
 *
 * Claude Code runs two SessionStart hooks: `harness-check` (an unadopted project
 * is offered the setup steps) and `role-hint` (the session title hints the
 * role). DSH has no shell hook layer, so both are injected once per session
 * from `agent/pre-step`, with the same marker machinery as the bootstrap.
 *
 * This module is pure: fs reads only, no ctx services, no spawn. The wiring
 * decides when to call it.
 */

import { createHash } from 'node:crypto'
import { readFileSync, statSync } from 'node:fs'
import { dirname, join, resolve } from 'node:path'

const SECTION_LABEL = 'секция «OpenSpec и superpowers» в CLAUDE.md'
const SECTION_RE = /^##[ \t]+OpenSpec и superpowers[ \t]*\r?$/m

/** Project ownership signals, in the order they are reported. */
const SIGNALS = [
  { kind: 'dir', name: 'openspec', label: 'openspec/' },
  { kind: 'dir', name: '.codegraph', label: '.codegraph/' },
  { kind: 'section', name: 'CLAUDE.md', label: SECTION_LABEL },
]

/** Keyword classes, highest priority first; the first matching class wins. */
const ROLE_KEYWORDS = [
  ['admin', ['jira', 'гант', 'спринт']],
  ['qa', ['стенд', 'прогон', 'скриншот', 'макет']],
  ['analyst', ['тз', 'oq', 'спека', 'методика']],
  ['dev', ['срез', 'issue', 'pr', 'тест', 'миграция']],
]

/** `pr` is too short for a substring match: it must be a whole word. */
const PR_WORD = /\bpr\b/u

function exists(path) {
  try {
    statSync(path)
    return true
  } catch {
    return false
  }
}

function isDirectory(path) {
  try {
    return statSync(path).isDirectory()
  } catch {
    return false
  }
}

function readText(path) {
  try {
    return readFileSync(path, 'utf8')
  } catch {
    return undefined
  }
}

function hasSection(text) {
  return typeof text === 'string' && SECTION_RE.test(text)
}

function findRepoRoot(cwd) {
  let dir = resolve(cwd || '.')
  for (;;) {
    if (exists(join(dir, '.git'))) return dir
    const parent = dirname(dir)
    if (parent === dir) return null
    dir = parent
  }
}

/**
 * Whether the project around `cwd` is wired into the harness.
 *
 * Walks up to the nearest `.git` (directory or file — worktrees use a file).
 * Outside any repository the answer is "adopted" so the check stays silent.
 * @param {string} cwd - session working directory
 * @returns {{adopted: boolean, root: string|null, missing: string[]}}
 */
export function detectAdoption(cwd) {
  const root = findRepoRoot(cwd)
  if (root === null) return { adopted: true, root: null, missing: [] }

  const missing = []
  for (const signal of SIGNALS) {
    const present =
      signal.kind === 'dir'
        ? isDirectory(join(root, signal.name))
        : hasSection(readText(join(root, signal.name)))
    if (!present) missing.push(signal.label)
  }
  return { adopted: missing.length === 0, root, missing }
}

/** Non-blocking harness-check text: what is missing and how to set it up. */
export function buildHarnessCheckText(root, missing) {
  const absent = Array.isArray(missing) ? missing : []
  return [
    `[dsh-harness] Проект ${root} не подключён к обвязке: нет: ${absent.join('; ')}.`,
    'Предложи владельцу настройку: openspec init --tools agents, codegraph init и секцию «OpenSpec и superpowers» в CLAUDE.md.',
  ].join(' ')
}

function matchesKeyword(text, keyword) {
  return keyword === 'pr' ? PR_WORD.test(text) : text.includes(keyword)
}

/**
 * Guess the session role from the first user message.
 *
 * Keywords are matched case-insensitively; Russian keywords, `jira`, `issue`,
 * `oq`, and `тз` are substrings, `pr` is a whole word only.
 * @param {string} firstUserText
 * @returns {'dev'|'admin'|'analyst'|'qa'|null}
 */
export function detectRole(firstUserText) {
  if (typeof firstUserText !== 'string' || firstUserText.trim() === '') return null
  const text = firstUserText.toLowerCase()
  for (const [role, keywords] of ROLE_KEYWORDS) {
    if (keywords.some((keyword) => matchesKeyword(text, keyword))) return role
  }
  return null
}

/** Role-hint text: a concrete role, or one question with the four variants. */
export function buildRoleHintText(role) {
  if (role) return `[dsh-harness] Роль сессии: ${role}. Вызови skill role. Если не так — скажи.`
  return (
    '[dsh-harness] Роль сессии неясна. Вызови skill role: dev — код, issue, PR, тест, миграция; ' +
    'admin — Jira, Гант, спринт; analyst — ТЗ, OQ, спека, методика; qa — стенд, прогон, скриншот, макет. ' +
    'Задай владельцу один вопрос с этими четырьмя вариантами.'
  )
}

/**
 * Whether a message was produced by the harness itself (bootstrap, a previous
 * injection, or the legacy Claude Code prefix). Such a message is not the
 * "first user message" for the role hint.
 */
export function isHarnessMessage(text) {
  if (typeof text !== 'string') return false
  return (
    text.startsWith('<!-- DSH-HARNESS-') ||
    text.includes('[dsh-harness]') ||
    text.includes('[claude-harness]')
  )
}

/**
 * Idempotency marker for a pre-step injection.
 * @param {string} text - injection body, hashed to make the marker unique
 * @returns {{marker: string, body: string}}
 */
export function makePrestepMarker(text) {
  const value = typeof text === 'string' ? text : String(text ?? '')
  const hash = createHash('sha256').update(value).digest('hex').slice(0, 16)
  const marker = `<!-- DSH-HARNESS-PRESTEP:${hash} -->`
  return { marker, body: `${marker}\n${value}` }
}